The Wind Wing was conceived as means of converting wind energy into electrical energy using a minimal displacement of mass.
It was belief of the inventor that a vertical symmetrical unarticulated airfoil, capable of rotating around a vertical shaft, could be engineered to oscillate in the wind. And that following Faraday's Law of induction, part of a coil attached to the airfoil's trailing edge would, in the presence of a nearby magnet, have a voltage induced within it. That wind energy might be converted into electrical energy with such a minimal movement of mass raised the potential that it also might produce a simpler, more reliable and less expensive alternative to other methods of exploiting wind energy.
A small wind tunnel was constructed using a variable speed DC (automobile radiator) fan, and different symmetrical unarticulated airfoil shapes were fabricated and tested. None was able to achieve oscillation.
The problem is that, as a symmetrical unarticulated airfoil with a zero angle of attack to the wind rotates, lift diminishes in the direction its tail rotates; while at the same time it increases in the reverse rotational direction. Most symmetrical unarticulated airfoils will flutter or vibrate, but they will not oscillate across any significant angular range.
This testing did reveal however, that the forces keeping an symmetrical unarticulated airfoil with its chord parallel to the wind inside a structure surrounding it were stronger than anticipated. This led to two coincident efforts. The first was to develop a spoiler which could, in synchronization with a symmetrical unarticulated airfoil's rotation, disrupt the lift on one side and then the other. Any angular displacement, which could be initiated by discontinuities in the wind, would then be magnified until steady state oscillations would develop. The second was to take advantage of web accessible computational fluid dynamics programs (JavaFoil, NASA FoilSim, etc). These revealed that by carefully selecting and positioning three vertically positioned airfoils close to certain NACA 4-digit symmetrical airfoils, wind velocity in specific sections of the channels between them would be increased, and static pressure decreased to shocking degrees.
To as much as possible maintain this geometry, while still capturing wind energy and converting it into mechanical energy, a scheme of segmenting and expanding the center airfoil into a Forward nacelle, an oscillating part (here named the Oscillating wing) and an Aft nacelle was invented. When a model of incorporating this scheme was constructed and tested, the Oscillating wing oscillated over a range of almost 60 degrees. No spoiler was required and the effort to develop one was abandoned.
Coincident with these developments, a method of wrapping the coil around the Oscillating wing, such that it would allow magnets fore and aft of its aft side was invented. It was nearly simultaneously recognized that a iron support for these magnets, virtually defaulted into becoming a permanent magnet dipole, a arrangement that creates a path for magnetic flux between the outside poles of two similarly oriented magnets or arrays of magnets. This allowed that flux density in the magnetic field through which the aft side of the coil would oscillate could be virtually doubled, virtually doubling the voltage induced in the coil when the Oscillating wing rotated. This arrangement was named the Permanent magnet dipole assembly, abbreviated PMDA
At some point it became apparent that such a machine could not only cost very little compared to other methods of converting wind energy into electrical energy, but could be fabricated by almost any community anywhere in the world using local craftspeople and mostly locally available materials. The potential that this could provide meaningful amount of electricity to a significant portion of the estimated 25-30% of the world currently without it became a dominant objective.
Pursuing this objective, it was recognized that a virtually abandoned (in the early 1900s) technique of creating strong magnets, called “compound magnets” could be employed to produce the magnets for Wind Wings in these communities. And that aluminum soft drink cans could be melted (aluminum having a relatively low melting point, low specific gravity and high conductivity), drawn into wire, and then coated with a combination of locally available ingredients to produce magnet wire. Given this, it appears that Wind Wings capable of providing sufficient electricity to light up one or two rooms or charge the battery of a small computer or smartphone can be fabricated in many parts of the world for as low as $20. This is the basis of the name, “the $20 Model.”
As representative of other models, that will benefit from advanced materials and fabrication capabilities, and because it appears a 6-foot high Wind Wing, attractive for single family homes in the United States can be professionally fabricated for as low as $500, it was decided to name these other models the “$500 and up Model.”
Once patent rights are secured, the inventor plans to allow communities worldwide fabricating $20 Models for their own use to do so freely.
Although there were indications that the oscillations that were observed in the model were caused by the build up of eddy currents immediately behind the Oscillating wing, it was decided to test this theory by mounting the model on the top of the inventor's car, driving up and down an abandoned airfield, and making videos of its behavior. By itself this exercise showed the machine's structure to be highly robust—an essentially foamboard and paper model 18-inches high withstanding apparent wind speeds in excess of 50 mph. Also, if one accepts the ability to withstand stress an indication of reliability, this machine is likely to prove highly reliable.
When the videos were later analyzed with a motion analysis program (Tracker), they showed that the frequency of oscillations asymptote at approximately 10 oscillations per second in the 30-35 MPH apparent wind range—indicating the machine likely to not require any additional mechanism to protect itself above 30 MPH, as do wind turbines by feathering their blades and turning their axes of rotation perpendicular to the wind.
The videos along with data from the computational fluid dynamics programs also allowed some quantification of the work being transferred from the wind to the mechanical motion of the Oscillating wing. They showed mechanical energy output from the same frontal area of the same speed wind to be in the same range of that achieved by well-developed small (1000 watt) wind turbines. This was a surprise.
The videos, along with the computational fluids dynamics programs also appear to confirm that what causes the Oscillating wing to oscillate is a build up of eddy currents inside the machine immediately aft of the more exposed corner of the Oscillating wing. As this grows, it disturbs the flow of air forward of itself on that side, catastrophically destroying the low local static pressure, allowing the lift on the other side to dominate and the Oscillating wing to rotate in that direction. As far as is known to the inventor, this is the only instance where eddy currents of wind have been employed to initiate and regulate wind energy to mechanical energy conversion.
Finally, there appears little question that with better engineering the Wind Wing can be substantially improved upon. And that as a project for appropriate US Government resources it would not only help the people of the planet, and indeed the planet itself, but give the United States a position of prestige in the fight against global warming that it has not enjoyed since Apollo 11, 40 years ago.